This invention relates to a lubricating device and method for lubricating high speed and/or low pitch chain type conveyors and more particularly to a lubricating device in which a rotatable sprocket means having a pump body connected thereto is adapted to rotate about a shaft means, to provide shots of lubricating fluid to a conveyor chain or other system while the chain or system is in operation.
When lubricating a chain having high speeds (e.g., 120 ft./minute) and/or small pitch (e.g., 2 inches or less in pitch) it has been found that problems arise with lubricating systems presently available. In some instances the lubricating pumps are inadequate because too many shots of lubricating fluid are required over a relatively short period of time. Other lubricating pumps presently available cannot be recycled fast enough to provide the required shots of lubricant so that portions of a chain or system to be lubricated fail to receive the necessary lubrication.
It also has been found that conventional trip devices such as limit switches are not satisfactory with conveyor systems involving high speeds. Unfortunately, these switches do not provide the efficient operation that is necessary for this particular type conveyor lubrication application. While other means are available for activating a lubricating device, e.g., photoelectric cell, they are either too costly, too complicated in structure or necessitate an excessive amount of maintenance.
Another problem relates to the play or movement in the chain conveyor when it is in operation during the course of which the chain can move laterally or vertically within certain tolerances. With larger chains this movement presents no significant problem, however, with small pitch chains, this play or variation in chain location causes problems in lubricating the desired area on the chain.
Another area of concern in applications involving high speed conveyor systems is that the lubricating fluid dispensing means should move at substantially the speed of the conveyor chain so that when a lubricating fluid is ejected from a fluid discharge nozzle it will deliver what is known as a clean shot to that portion of the conveyor system to be lubricated. Failure to deliver clean shots of lubricant to the system provides serious disadvantages. If the lubricant is not deposited properly on the conveyor, the shot of fluid will often shatter, whereby the fluid dispenses in an undesired random manner on the conveyor, thereby causing inefficient lubrication in addition to causing problems of drippage which necessitate accessory devices to catch the excess lubricant. The shattering of a shot of lubricating fluid has been found to occur when there is a significant difference in velocity between the chain speed and the speed of the lubricating fluid discharge means.
It is desired to have a lubricating device that can deliver clean shots of lubricating fluid at desired locations on a high speed and/or low pitch chain conveyor or system in which the fluid discharge port on the lubricating device travels at substantially the same velocity as the chain to be lubricated. Further, it is desired that the speed of the chain and the discharge means of the lubricating device be synchronized so that both travel at substantially the same speed irrespective of whether the conveyor speed is purposely changed or a change in conveyor speed arises due to an increase or decrease in load on the conveyor chain.
It is also desired to have a lubricating device which will allow lubricating fluid to be delivered to the appropriate spot on a chain while taking into account the play in the chain or conveyor system.